The present invention relates to a suspension assembly for an automotive vehicle. The invention also concerns an automotive vehicle comprising such a suspension assembly.
Automotive vehicles such as trucks are often equipped with suspension systems using leaf springs. Those leaf springs are bound to the vehicle by spring hangers. A leaf spring is generally articulated on a spring hanger at both ends.
Each spring hanger, also named “bracket”, is generally provided with two mounting flanges. A leaf spring, also named “suspension arm”, is mounted between the two flanges. As the suspension arm needs to be mounted with a mounting clearance with respect to the bracket on one side of the suspension arm, the space between the flanges of the bracket is larger than the width of the suspension arm. In normal use, no clearance is allowed between the suspension arm and the flanges of the bracket. The suspension arm is bound with the bracket by a bolt mounted through bores in the flanges of the bracket and through the suspension arm. To eliminate the mounting clearance, a spacer is mounted in a bore of one flange and pressed against, a side of the suspension arm, by screwing the bolt.
As the suspension arm transmits high forces, vibrations and displacements to the suspension assembly, the spacer wears the bracket in the contact area with the spacer. Wear on the bores of the bracket leads to greater displacements of the suspension arm with respect to the bracket and to failures.
FR-1 138 218 describes a suspension assembly comprising a bolt mounted through flanges of the bracket and through the suspension arm. Two rubber bushes are mounted, between the bolt and the suspension arm, and pressed against one flange of the bracket by the bolt head. This assembly permits to absorb vibrations between the suspension arm and the bolt and to eliminate the mounting clearance.
However, this assembly does not prevent wear on the bracket provoked by the head of the bolt inserted in the flange of the bracket.
It is desirable to provide a suspension assembly for an automotive vehicle, allowing the mounting of the suspension arm with the mounting clearance and the elimination of the clearance by pressing a movable part against the suspension arm, while preventing this part from provoking wear on the bracket, caused by small displacements of the movable part with respect to the bracket.
To this end, the invention concerns, according to an aspect thereof, a suspension assembly for an automotive vehicle comprising a fixed bracket, a suspension arm mounted between two mounting flanges of the bracket, a spacer mounted in a bore of a flange of the bracket and an articulation shaft mounted through the flanges, the suspension arm and the spacer. This suspension assembly is characterized in that the spacer comprises an inner ring in which the articulation shaft is mounted, in that an end face of the inner ring is adapted to be pressed, along a longitudinal axis of the shaft, against a lateral face of the suspension arm, and in that the spacer comprises, between its inner ring and the bore in which the spacer is mounted, an deformable sleeve, deformable along said longitudinal axis under a shear effort and adapted to slide with respect to the inner ring or to the bracket, along said longitudinal axis.
The sleeve being adapted to slide means that it can be displaced with respect to at least one of the inner ring and of the bracket during the mounting process, so that, from an initial position of the inner ring allowing for a clearance, the inner ring of the spacer can be displaced to a position where it is pressed against a lateral face of the suspension, arm, which can be either a rigid part or a more elastic part such as a leaf spring, by sliding with respect to the deformable sleeve, or by sliding of the deformable sleeve with respect to the bracket. In use, the deformable sleeve absorbs efforts and small displacements of the inner ting with respect to the bracket, along the longitudinal axis of the articulation shaft, without movements at the interfaces between these parts. This prevents wear on the bracket.
According to further aspects of the invention which are advantageous but not compulsory, such a suspension assembly may incorporate one or several of the following features:
The suspension assembly comprises means to block displacements of the deformable sleeve with respect to the inner ring or to the bracket, along the longitudinal axis of the shaft.
The deformable sleeve is blocked in translation with respect to the bracket, along the longitudinal axis of the shaft, by a shoulder of the bore in which the spacer is mounted, this shoulder extending, radially and inwardly, between the deformable sleeve and the suspension arm.
The deformable sleeve is blocked in translation with respect to the bracket, along the longitudinal axis of the shaft, by an elastic ring mounted in a groove of the bore, in which the spacer is mounted, said ring extending, radially and inwardly, between, the deformable sleeve and the suspension arm.
The spacer comprises an outer ring fast with the bore in which the spacer is mounted, whereas the deformable sleeve is mounted .radially between the inner ring and the outer ring.
The deformable sleeve is blocked in translation with respect to the outer ring, along the longitudinal axis of the shaft, by an elastic ring mounted in a groove of the internal, face of the outer ring, said ring extending, radially and inwardly, between the deformable sleeve and the suspension arm.
The deformable sleeve is blocked in translation with respect to the outer ring, along the longitudinal axis of the shall by a shoulder of the outer ring, said shoulder extending, radially and inwardly, between the deformable sleeve and the suspension arm.
Translation of the deformable sleeve, along the longitudinal axis of the shaft, on an opposite side with respect to the suspension arm is blocked by an elastic ring which extends radially and inwardly with, respect to the bore or to the outer ring.
The deformable sleeve is adapted to slide with respect to the outer ring, along the longitudinal axis of the articulation shaft.
The deformable sleeve is blocked in translation with respect to the inner ring, along the longitudinal axis of the shaft, by an elastic ring mounted in a groove of the external surface of the inner ring, said ring extending, radially and outwardly, between the deformable sleeve and the suspension arm.
The deformable sleeve is blocked in translation with respect to the inner ring, along the longitudinal axis of the shaft, by a shoulder of the inner ring, said shoulder extending, radially and outwardly, between the deformable sleeve and the suspension arm.
Translation of the deformable sleeve, along the longitudinal axis of the shaft, on an opposite side with respect to the suspension arm is blocked by an elastic ring which extends radially and outwardly with respect to the inner ring.
The deformable sleeve comprises two coaxial elastic parts, whereas an internal stiffener is inserted between the two parts.
The deformable sleeve is made of polymer material.
The deformable sleeve is made of elastomeric material such as natural or synthetic robber material.
The deformable sleeve is deformable, under a shear effort, in rotation around the longitudinal axis of the articulation shaft.
The invention also concerns , according to an aspect thereof, an automotive vehicle comprising the above-mentioned suspension assembly.